// ==LICENSE-BEGIN==
// Copyright 2017 European Digital Reading Lab. All rights reserved.
// Licensed to the Readium Foundation under one or more contributor license agreements.
// Use of this source code is governed by a BSD-style license
// that can be found in the LICENSE file exposed on Github (readium) in the project repository.
// ==LICENSE-END==

export const fallback = <T>(...valueArray: T[][]) =>
    valueArray.reduce(
        (pv, cv) =>
            (Array.isArray(cv) && cv.length)
                ? cv
                : pv
        , []);
